Twin port conversion

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Breconbus
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Twin port conversion

Post by Breconbus » Sat Feb 23, 2019 1:07 pm

Hi
I am converting my 1600 single port to a 1641 twin port as the heads have gone. Going for the 12v conversion as the engine is now out and tried my best for 8 yrs on the 6v electrics
Questions are can I put a bigger fan blade unit into my single port shroud and do I need a bigger oil cooler.
Will the single port tin wear around the input manifolds work with the twin port manifolds

I am on a budget so trying to avoid a full new doghouse shroud if possible without overheating worries.

I have a 109 tooth flywheel with 200 mill clutch disc so I intend to change the clutch friction plate and keep the starter motor the same? I read that the 6v starter is strong enough to stand the 12v conversion.
The clutch housing is in very good nick, no play and springs are strong.

Any help appreciated

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clymoj
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Re: Twin port conversion

Post by clymoj » Sun Feb 24, 2019 10:47 am

I can’t answer many of your specific questions but the 1600 single port gets very good reviews as a bus engine compared to the 1641 twin port. If that helps to keep to a single port?


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clymoj
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Re: Twin port conversion

Post by clymoj » Sun Feb 24, 2019 11:17 am

As far as I know the twin port switches to the doghouse cooler so you’ll need a different fan shroud and tinwear. You can get a conversion which allows you to put later doghouse cooler and larger fan onto a single port engine, but I’ve not seen anything which allows you to do the same the other way around, and you wouldn’t want to because it wouldn’t be enough.

The doghouse cooling doesn’t have a bigger oil cooler it’s the same one just in a cooler airflow due to its position in the shroud. The shroud also changes the flow to make all cylinders cool more evenly, particularly increasing cooling to #3. If you were going to try and use a single port shroud with small fan and poorer oil cooler airflow then you could assume both the oil and head cooling wouldn’t be enough, hence why VW redesigned it. And a bigger fan won’t just fit into the older fan shroud, it comes as part of the upgrade to the doghouse style.

This is a good read if you like reading: http://www.vw-resource.com/oil_cooler.html

Hopefully that helps?


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Breconbus
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Re: Twin port conversion

Post by Breconbus » Sun Feb 24, 2019 2:37 pm

Hi thanks for the information. Very helpful on the cooling side. Any thoughts or experience on the starter motor or anyone else reading.
Cheers

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clymoj
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Re: Twin port conversion

Post by clymoj » Mon Feb 25, 2019 1:13 am

Again, I wouldn’t count myself as an expert but in lieu of other replies so far...

General verdict on the starter is it’ll be fine. There was a discussion a few days ago on this topic and the overall conclusion was that 6v starters (and fuel gauges) were fine on 12v.

Hopefully someone else will chip in too to validate things but this’ll get you, erm, started ;)


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Breconbus
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Re: Twin port conversion

Post by Breconbus » Mon Feb 25, 2019 8:38 am

Ok once again thanks. I ll stick with my 6v starter

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